feat: add private memory hygiene discipline

.agents/skills/memory-hygiene/SKILL.md

@@ -0,0 +1,67 @@
+---
+name: memory-hygiene
+description: >-
+  Agent-only discipline for keeping firstmate's private memory lean and robust.
+  Use before writing, rewriting, pruning, deduplicating, or otherwise leaning entries in data/captain.md or data/learnings.md.
+user-invocable: false
+metadata:
+  internal: true
+---
+
+# memory-hygiene
+
+Keep each private-memory entry at the essence of what future firstmate sessions need to act correctly.
+This skill owns entry shape for `data/captain.md` and `data/learnings.md` only.
+`AGENTS.md` section 6 owns knowledge routing and the files' inspect-then-update, rewrite-in-place contract.
+The `/stow` skill owns session sweeps, and `firstmate-coding-guidelines` owns repository-wide knowledge placement and one-owner discipline.
+
+## Entry standard
+
+- Record only the actionable rule or durable fact.
+- Strip emotion, emphasis, interpersonal interpretation, and incident drama.
+- Do not preserve that anyone was furious, shocked, disappointed, emphatic, or otherwise emotionally affected.
+- Preserve the operational instruction or evidence-backed fact that remains after the mood is removed.
+- Limit an entry to the rule or fact plus, at most, a one-line example or a `[[pointer]]` to its detailed source.
+- Put incident chronology, rationale, logs, and supporting narrative in their proper detailed source, not private memory.
+- Apply `firstmate-coding-guidelines`' one-owner rule when deduplicating memory.
+- Fold a new lesson into the existing entry it sharpens instead of adding a near-duplicate.
+- Rewrite or prune the owning entry in place so the file converges instead of growing as a log.
+
+## Update practice
+
+1. Use `AGENTS.md` section 6 to confirm that the knowledge belongs in one of these private-memory files.
+2. Inspect the current file and the candidate owning entry before writing.
+3. Search nearby entries for overlap, stale wording, and superseded variants.
+4. Reduce the new information to one actionable rule or durable fact.
+5. Rewrite the existing owner when one exists; add a new entry only when no owner exists.
+6. Remove superseded or duplicate wording in the same update.
+7. Read the result once more and cut any detail that does not change future action.
+
+Use a one-line example only when the rule would otherwise be ambiguous.
+Use a `[[pointer]]` when a future session may need evidence or context beyond the essence.
+Do not use either device to smuggle a narrative back into the memory file.
+
+## Before and after
+
+Before:
+
+> 2026-07-22: The captain was furious after an agent tried to deploy while checks were failing, and stated very firmly that this was completely unacceptable because the incident wasted hours and created a stressful rollback.
+
+After:
+
+> Require green CI before deployment. `[[deploy-incident-2026-07-22]]`
+
+The rewrite retains the future action and a route to evidence.
+It drops mood, drama, chronology, and commentary that do not change the rule.
+
+## Final check
+
+Reject the update if any answer is yes:
+
+- Does it describe emotion or intensity instead of changing future action?
+- Does it retell an incident beyond one short example or pointer?
+- Does another entry already own the same rule or fact?
+- Could the existing owner be sharpened instead of adding a new entry?
+- Did the file grow without stale or duplicate wording being considered?
+
+Private memory is a curated operating aid, not an incident log.

AGENTS.md

@@ -331,13 +331,15 @@ Route each piece of durable knowledge to its most specific home:
 
 | Kind of knowledge | Home |
 | --- | --- |
-| Captain preferences and working style | `data/captain.md`, inspected first and rewritten or pruned in place |
+| Captain preferences and working style | `data/captain.md`, inspected first, kept as deduplicated rule-only essence with no drama, and rewritten or pruned in place |
 | Project-intrinsic knowledge | that project's own `AGENTS.md`, via normal crewmate delivery, never hand-written by firstmate |
-| Fleet-local facts and gotchas only: load-before-doing procedures are skills; be-aware background is a learning; when in doubt, use a skill | `data/learnings.md`, inspected first and rewritten or pruned in place |
+| Fleet-local facts and gotchas only: load-before-doing procedures are skills; be-aware background is a learning; when in doubt, use a skill | `data/learnings.md`, inspected first, kept as deduplicated fact-only essence with no drama, and rewritten or pruned in place |
 | Knowledge generalizable to every firstmate user | the shared `AGENTS.md`, shipped via PR through the pipeline |
 | Task-scoped notes | backlog item notes, inspect first with `tasks-axi show <id> --full`, then replace the body with `tasks-axi update <id> --body-file <path>`, adding `--archive-body` when superseded prior state should remain recoverable, or hand-edit per the active backend |
 | Investigation findings | scout reports at `data/<id>/report.md` |
 
+Load `memory-hygiene` before writing or leaning `data/captain.md` or `data/learnings.md`; it owns the per-entry leanness standard while this section owns routing.
+
 When the captain invokes `/stow`, load the `stow` skill.
 It sweeps the current session for uncaptured durable knowledge, routes findings with this table, files undone next steps to the backlog, and reports whether the session is safe to reset.
 
@@ -783,6 +785,7 @@ These skills are not captain-invocable; they are conditional operating reference
 - `firstmate-codexapp` - load before coordinating a visible Codex Desktop thread, evaluating a Codex App backend request, or reconciling Codex Desktop host-tool smoke evidence for Firstmate work.
 - `skill-authoring-standard` - load before authoring or substantially editing any skill in this repo or any project, and before briefing a project crew to do so.
 - `firstmate-coding-guidelines` - load before changing firstmate's shared, tracked material, as defined by section 1's list, whether editing directly or briefing a crewmate for a firstmate-repo task.
+- `memory-hygiene` - load before writing, rewriting, pruning, deduplicating, or otherwise leaning `data/captain.md` or `data/learnings.md`.
 - `lavish-decision-boards` - load before creating or revising a captain-facing Lavish board that asks the captain to make decisions or provide structured feedback.
 - `eks-usage` - load before running `kubectl` or Amazon EKS commands, on an EKS IAM, authenticator, TLS, or connectivity error, or whenever the active cluster or context is uncertain.